all right, susan in new york, appreciate it. thank you. >>> new developments today in the shooting that killed a u.s. border patrol agent. the fbi now thinks he may have died by friendly fire. the 30-year-old man was shot and killed this week in arizona. officials initially said he and his colleagues who were wounded in the incident, came under fire after responded to a sensor that went off, but authorities say the only shell casings found at the scene were those belonging to the agents. >> you know, investigators have made progress into the investigation, into agent ivy's death and are looking into the possibility that it was a tragic accident, the result of friendly fire. the fact is the work of the border patrol is dangerous. all of us who wear the uniform know this and yet this special breed of men and women willingly put themselves in harm's way to serve their country and to protect their communities. against those who wish to do us harm. >> that news comes as homeland security secretary janet napolitano travels to arizona